1. Field of the Invention
The present invention relates to food containers and, more particularly, to a food container sealing structure, in which the coupling flange of the container body has endless concave portions extended around the container body and arranged at right angles, and the coupling flange of the cover has endless convex portions extended around the cover and arranged at right angles for engaging the endless concave portions of the coupling flange of the container body to seal the container body.
2. Description of the Related Art
Vacuum-formed plastic containers are commonly made in the form of a box, cup, or bowl for use to keep food fresh. When carrying fluid, jelly-like, or liquid food in a plastic container, the container must be sealed, preventing a leakage of contained food. FIG. 1 shows a cup-like plastic food container 1 according to the prior art. The cup-like plastic food container 1 comprises a cup body 11 holding a liquid food 12, and a film covering 13 of aluminum foil or plastic film sealed to the top open side of the cup body 11. When opened the film covering 13, the film covering 13 cannot be sealed to the cup body 11 again. FIG. 2 illustrates another structure of plastic food container 2 according to the prior art. According to this design, the plastic food container 2 comprises a cup body 21, and a cover 22 sealed to the top open side of the cup body 21. The cup body 21 has a coupling flange 211 extended around the top opening. The cover 22 has a peripheral coupling flange 221 coupled to the coupling flange 211 of the cup body 21. If the plastic food container 2 is used to hold a liquid food 23, a heat sealing apparatus or the like must be used to seal the coupling flanges 211;221. When sealed, the user must use a scissors or cutter means to open the cover 22. When opened, the cover 22 cannot be sealed to the cup body 21 again.
FIGS. 3 and 3 show a food container 3 constructed according to U.S. Pat. No. 6,056,138, entitled “TRIPLE SEAL CONTAIENR”. According to this design, the food container 3 comprises a container body 31 and a cover 32 covered on the container body 31. The cover 32 is made from plastics by a vacuum-forming machine, having a flange 321 extended around the periphery and a locking lip 322 protruded from the free end of the flange 321. When attaching the flange 321 of the cover 32 to the rim 311 of the container body 31, the locking lip 322 is hooked on the free end of the rim 311 of the container body 31. This design of food container is still not satisfactory in function. The main drawbacks of this design of food container are as follows:
1. When opening the cover 31, the user must use the fingers to disengage the locking lip 322 from the rim 31 of the container body 31. When pulling the locking lip 322 away from the rim 311 of the container body 31 with the fingers, the locking lip 322 may injure the fingers.
2. When the cover 32 closed on the container body 31, a gap 34 is left in the connection area 33 between the flange 321 of the cover 32 and the rim 311 of the container body 31. If the food container falls down, contained liquid food may leak out of the food container 3 through the gap 34.